Feeds

World's most advanced rootkit penetrates 64-bit Windows

Windows driver signing mincemeat

The Power of One eBook: Top reasons to choose HP BladeSystem

A notorious rootkit that for years has ravaged 32-bit versions of Windows has begun claiming 64-bit versions of the Microsoft operating system as well.

The ability of TDL, aka Alureon, to infect 64-bit versions of Windows 7 is something of a coup for its creators, because Microsoft endowed the OS with enhanced security safeguards that were intended to block such attacks. The rootkit crossed into the 64-bit realm sometime in August, according to security firm Prevx.

According to research published on Monday by GFI Software, the latest TDL4 installation penetrates 64-bit versions of Windows by bypassing the OS's kernel mode code signing policy, which is designed to allow drivers to be installed only when they have been digitally signed by a trusted source. The rootkit achieves this feat by attaching itself to the master boot record in a hard drive's bowels and changing the machine's boot options.

“The boot option is changed in memory from the code executed by infected MBR,” GFI Technical Fellow Chandra Prakash wrote. “The boot option configures value of a config setting named 'LoadIntegrityCheckPolicy' that determines the level of validation on boot programs. The rootkit changes this config setting value to a low level of validation that effectively allows loading of an unsigned malicious rootkit dl file.”

According to researchers at Prevx, TDL is the most advanced rootkit ever seen in the wild. It is used as a backdoor to install and update keyloggers and other types of malware on infected machines. Once installed it is undetectable by most antimalware programs. In keeping with TDL's high degree of sophistication, the rootkit uses low-level instructions to disable debuggers, making it hard for white hat hackers to do reconnaissance.

One of the advanced protections Microsoft added to 64-bit versions of Windows was kernel mode code signing policy. Microsoft also added a feature known as PatchGuard, which blocks kernel mode drivers from altering sensitive parts of the Windows kernel. TDL manages to circumvent this protection as well, by altering a machine's MBR so that it can intercept Windows startup routines.

Prevx has more here. And for an in-depth technical analysis from Microsoft researcher Joe Johnson check out this PDF. ®

Designing a Defense for Mobile Applications

More from The Register

next story
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
Four fake Google haxbots hit YOUR WEBSITE every day
Goog the perfect ruse to slip into SEO orfice
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.